1. Field of the Invention
This invention relates to a sailing craft, and particularly to a sailing craft without a rudder which can be effectively steered by fore-and-aft tilting of sail and keel. Additionally, the craft is hydrodynamically symmetrical fore and aft. It moves through the water identically in either direction. It is thus capable of performing a new sailing maneuver called a "tack aback. " In a tack aback, the craft changes its sailing direction (i.e., tacks) by rotating its boom to the front of the craft and putting the sail aback. This stops the craft and causes the craft to move aback in the general direction from which it came. In a tack aback, unlike all other tacking maneuvers, the wind continues to blow on the same side of the craft throughout the maneuver.
2. Description of the Prior Art
Steering a sailboat without the aid or presence of a rudder is accomplished on a sailboard by tilting the mast (with sail) fore and aft. But the board itself is not hydrodynamically symmetrical fore and aft. Sailboards generally have both a midship fixed fin keel and one aft fixed fin rudder. Their stern and bow are not interchangeable. Sailboards sail only in a forward direction. They cannot tack aback.
U.S. Pat. No. 4,766,830 (Kunz) teaches a sailboat which has twin inflatable hulls for floatation of a catamaran. Each inflatable hull is essentially hydrodynamically symmetrical fore and aft. But the sailboat of the '830 patent is not symmetrical. It has a movable rudder for steering affixed to its stern, and the boat disclosed in the '830 patent cannot tack aback.
U.S. Pat. No. 4,102,287 (Ferris) teaches a catamaran whose mast can swing from straight down in the water to straight up so a capsized boat need not be righted. The swing of the sail is not used for steering and the hulls are not hydrodynamically symmetrical fore and aft. The boat is steered by rudders and the boat cannot tack aback.
U.S. Pat. No. 3,972,300 (Adamski) teaches a sailing craft where mast and keel are free to rotate from side to side so the hull remains level atop the water. This craft is not steerable by mast/keel tilt. It has an aft rudder and is asymmetrical fore and aft so it cannot tack aback.
U.S. Pat. No. 3,986,473 (Truzzi) is a tiller bar steered craft with auxiliary sail whose sail forces aid, to some extent, the steering. The sail/rudder does not tilt. The craft is asymmetrical fore and aft, and cannot tack aback.